Preparation of waterproof and air-permeable silicalite-1/PDMS/PTFE membrane by casting method for metal-air battery

The electrochemical performance of metal-air batteries is sensitive to environmental humidity. In this paper, waterproof and air-permeable polydimethylsiloxane (PDMS)/polytetrafluoroethylene (PTFE) membranes were prepared for alleviating these issues in metal-air battery. The effects of membrane fillers (hydrophilic SiO2, hydrophobic SiO2, activated carbon, silicalite-1) on the water vapor and air permeability of PDMS membranes were investigated. The results showed that, adding an appropriate amount of silicalite-1 can improve the waterproof and air permeability of PDMS membrane. The silicalite-1/PDMS membrane significantly reduces the running resistance of the battery, and improves the cycle number of Li-air batteries by 130% and that of Zn-air batteries by 43% in the air environment (40% RH, 25°C). The polarization voltage is also significantly reduced, indicating great potential in applications.